Definitioner

PLEX

A Pilot License Extension (PLEX) is an item that adds 30 days of game time to an EvE Online account. It is freely traded like any other in game item. CCP accepts to convert in game PLEXES to real money in case disasters and emergencies happen.

NEISIN

A New Eden Interstellar Securities Identification Number (NEISIN) uniquely identifies a security. While its structure is identical and strictly compliant with "real life" ISINs, NEISINs are tailored to New Eden investments and contracts.